As was mentioned in the previous section, the Attribute Editor provides a tabular view of the attributes of all features in a layer. Similar to a spreadsheet, this powerful component of Global Mapper’s vector data management functionality includes tools for manually editing attributes, joining attributes from an external file, creating new attribute fields, sorting attributes, creating a query, and much more. In this lesson, we will spend some time exploring the Attribute Editor before creating a query to isolate a subset of a layer.
Introducing the Attribute Editor
- If necessary, remove any loaded data from Global Mapper (Ctrl+U)
- Load the following shapefile: *Intro to Global MapperDataParcelsBlack Mountain Parcels.shp
- In the Control Center, select the parcels layer and click the Edit Attributes button
- The Attribute Editor will initially appear as a floating window. Click and hold its toolbar and drag it to the point where the cursor is within the downward pointing arrow in the middle of the screen. This will dock the Attribute Editor below the map.
Follow along with this video as the instructor introduces the various components of the Attribute Editor
If multiple vector layers are selected before clicking the Edit Attributes button in the Control Center, a separate tab for each table is displayed in the Attribute Editor window
Building a Query
As we saw in the preceding video, the Attribute Editor’s sorting and selecting functionality is often the quickest and most straightforward way to create a subset of a vector layer. However, when a more complex or multifaceted search is required to isolate relevant features, a structured query is a more effective option.
- With the parcels layer still loaded and the Attribute Editor open, click the Search button on the left side of the Attribute Editor toolbar
The Search function can also be accessed from the Tools toolbar and from the Search menu
- From the list of Attributes on the left side of the window, select LAND_USE and click the + sign button below the window
This populates the Query window with the name of the attribute enclosed in % signs
- In the Operations section, click the = button
This is automatically added to the query
- In the Values section on the right side of the window, click the Load Values button
This lists all of the values that are present in the LAND_USE attribute
- From this list, choose Residential and click the + sign button to add this value to the query
The word residential is enclosed with quotation marks to indicate that the query will be based on an exact text match
- Click the Search button
The Attribute Editor table is now filtered to show just the residential properties with the number of results (3,605) displayed in the lower right corner of the window.
Now we will add a second component to this query to find the most expensive residential properties.
- In the Search Vector Data window, click after ‘Residential’ in the Query field
- Click the ‘and’ button in the Operators section
- From the Attributes list, double-click TAXVALUE
Double-clicking eliminates the need to click the + button
- In the Operations section, click the > button
- After > in the Query window, type 500000
Because the TAXVALUE attribute does not contain a list of repeated values, the Load Values function is not relevant
- Click the OK button to run the query and close the Search Vector Data window
Note there are now only 349 rows in the Attribute Editor
Finally, we will copy the query results into a new layer.
- In the Attribute Editor toolbar, click the Select All button
- Use the Ctrl+C and Ctrl+V keyboard shortcuts to copy and paste the results
- When prompted to choose a layer into which to paste the results, choose Create New Layer to Paste To and click the OK button
- Type the layer name Expensive Properties and click the OK button
- In the Control Center, uncheck the original parcels layer
- Save a workspace called Expensive Properties in your My Maps folder
- The Attribute Editor provides access to an extensive collection of Global Mapper’s attribute management tools
- Beyond just an editor, it offers the means to interact with a tabular display of a layer’s attributes
- For more powerful attribute filtering, the software’s query tool can be employed to identify features based on multiple attribute variables
- Click here for more information